import java.io.FileWriter;
import java.io.IOException;
import com.groupdocs.parser.Parser;
import com.groupdocs.parser.data.*;
import com.groupdocs.parser.options.*;
...
...
try (Parser parser = new Parser("/path/document.docx")) {
    try (TextReader reader = parser.getFormattedText(new FormattedTextOptions(FormattedTextMode.Markdown))) {
        String content = reader.readToEnd();
        try {
            FileWriter myWriter = new FileWriter("/path/word-to-markdown.md");
            myWriter.write(content);
            myWriter.close();
        }
        catch (IOException e) {
            e.printStackTrace();
        }
    }
}